Update README.md for UMD bundle v0.2.1

Author: stdlib-bot

README.md

@@ -112,7 +112,7 @@ The use of the term `n-1` is commonly referred to as Bessel's correction. Note,
 To use in Observable,
 
 ```javascript
-stdevtk = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@umd/browser.js' )
+stdevtk = require( 'https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@v0.2.1-umd/browser.js' )
 ```
 
 To vendor stdlib functionality and avoid installing dependency trees for Node.js, you can use the UMD server build:
@@ -124,7 +124,7 @@ var stdevtk = require( 'path/to/vendor/umd/stats-base-stdevtk/index.js' )
 To include the bundle in a webpage,
 
 ```html
-<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@umd/browser.js"></script>
+<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@v0.2.1-umd/browser.js"></script>
 ```
 
 If no recognized module system is present, access bundle contents via the global scope:
@@ -241,7 +241,7 @@ var v = stdevtk.ndarray( N, 1, x, 2, 1 );
 <script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/random-base-randu@umd/browser.js"></script>
 <script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/math-base-special-round@umd/browser.js"></script>
 <script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/array-float64@umd/browser.js"></script>
-<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@umd/browser.js"></script>
+<script type="text/javascript" src="https://cdn.jsdelivr.net/gh/stdlib-js/stats-base-stdevtk@v0.2.1-umd/browser.js"></script>
 <script type="text/javascript">
 (function () {